Place the rinsed pinto beans in the Instant Pot and add the water. Secure the lid and set the valve to sealing. Cook on high pressure for 45 minutes.
Once the cooking time is complete, allow the pressure to release naturally for about 15 minutes, then carefully switch the valve to venting to release any remaining pressure.
Open the lid and drain the beans, reserving about 1 cup of the cooking liquid.
In the same pot, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 5 minutes. Stir in the minced garlic and cook for another minute.
Add the drained beans back to the pot along with cumin, chili powder, and salt. Mash the beans with a potato masher or fork to your desired consistency, adding reserved cooking liquid as needed to achieve a creamy texture.
Taste and adjust seasoning if necessary. Serve warm, garnished with fresh cilantro and lime wedges if desired.